This invention relates to latching devices for securing shank-and-socket type couplings such as for connecting auger sections end-to-end to form strings of axially aligned auger sections used in auger mining machines to rotate a cutting head and progressively drive an auger assembly forward into a mineral deposit while removing the mined material by the auger strings. More particularly, the invention relates to a latching device of minimum radial dimension relative to the auger section to fit within the cross sectional limits of the hole being cut by the auger machine, to a mechanism for automatically releasing a plurality of such latching devices used with a plurality of parallel, generally coplanar auger strings formed of separate auger sections coupled together end-to-end in axially aligned relation.
The invention has particular utility in connection with auger machines for mining lateral seams or veins of mineral, such as coal, and especially to a machine usually located in an open pit that advances a rotary cutting head progressively laterally into the seam of coal while conveying the dislodged coal rearwardly from the cutting head by helical auger flights in known manner. Additional auger sections are added as needed depending upon the extent of the advance of the cutting head into the coal seam, to form a string corresponding to the depth of the hole.
Many such auger mining machines have multiple rotary cutting heads journaled in a rigid frame with their respective axes parallel and generally coplanar. The resulting assembly is advanced as a unit into the earth to cut a relatively wide hole as the mining progresses. Where multiple cutting heads are used, normally two or more separate strings of auger sections extend from the main body of the machine to the cutting head assembly to rotate the plurality of cutting heads simultaneously and to exert a thrust to advance the cutting heads into the mineral deposit to be mined.
New developments in the economics of coal mining have created conditions where it is now feasible to mine coal from relatively thin seams that in the past would have been bypassed as being economically unfeasible to mine. The reduced diameters of the cutting heads and auger flights for mining such thin seams have necessitated the provision of associated equipment so that it will fit within the cross section of the hole through which the auger strings are advanced. This associated equipment includes the devices for latching the couplings between axially aligned auger sections in the auger strings.
Normally the interconnected auger sections have a socket portion on one end of each section and a cooperating mating shank on the opposite end. The shank fits into the socket recess of the next section and a latch pin extending transversely of the auger axis is passed through the wall of socket portion and into a recess formed in the shank. Such a connection is illustrated and described in U.S. Pat. No. 3,278,236.
A lever is usually provided for retracting the latch pin from the shank to permit uncoupling of the sections, as when the cutting head is being withdrawn from the hole at completion of the mining of the seam. As the auger string is withdrawn, the auger sections of each string must be sequentially removed from the machine by uncoupling the sections and lifting the rearmost section from the machine.
Prior art devices have often necessitated the retraction of the latch pin by a worker who holds the pin while the shank and socket are uncoupled from one another. This is an awkward and time-consuming operation particularly when auger sections of a plurality of strings must be unlatched, and involves certain danger to the worker. Mechanical uncoupling mechanisms have been heretofore provided for the purpose of depressing unlatching levers of a plurality of generally parallel auger sections and hold them depressed in unlatching position during the uncoupling operation, but problems arise when the levers of the unlatching devices of generally parallel auger sections are out of their desired essentially coplanar alignment, as because the axes of such auger sections are not in essentially coplanar relationship because one or more are deflected out of such relationship because they have more or less mined material around them than others, or because of misalignment of the large auger mining machine at the job site, or because deflection of the auger guide that has caused the auger axes to displace from the desired coplanar relationship. The unlatching levers may also be displaced out of their desired essentially coplanar relationship because they have not been stopped in the same angular position, preferably in the uppermost position, on halting of rotation of the auger strings. Even though the driving means for the auger strings is geared to rotate them and halt their rotation simultaneously, occasionally the auger sections to be unlatched do not all halt in the same angular positions, as due to play in the apparatus or in the connections of the auger sections as due to wear.
For such reasons, an uncoupling member intended to operate three unlatching levers simultaneously might unlatch only two while another one that is out of coplanar relationship with the others is not completely depressed, so all auger sections are not simultaneously unlatched, thus necessitating manual unlatching of the unlatched sections with attendant delay and possible danger.
The present invention resolves the difficulties indicated above and affords other features and advantages heretofore not obtainable.